We don't have expert witnesses otherwise this issue would have been solved some time ago.
I believe we have people making assumptions based on observations, myself included.
Human nature to fill in the blanks of understanding.
We dont need "expert witnesses"
All we need is for one or more of those who say they own these "magic rifles" to fire them with witnesses that can say they saw them fire smaller groups at long range than the gun could fire at close range.
Then they can let someone else run the same test with the same rifle to make sure it wasn't flawed
This doesn't require a lot of calculations and charts
It requires simple proof by
doing it in front of a crowd
And yet not one has taken the opportunity to prove it to the world
And no one will